Two years ago this summer, a denitrifying bioreactor was installed by South Dakota State University on the Hefty brothers’ farm near Baltic as part of a research project to reduce nutrients runoff leaving fields through subsurface tile drainage. And after two years of research at that site, SDSU’s Water Resource Institute researchers are pleased with the results.
At today’s Ag PhD Field Day near Baltic, Jeppe Kjaersgaard, an assistant professor of Agricultural and Environmental Water Management at SDSU said that the bioreactor at the site is removing between 60-75% of the nitrates leaving the drainage system on average. During peak flow periods (high rainfall events) the bioreactor will remove around 40% and during periods of low flow they are seeing nitrogen removal rates of around 90%.
“On average, the nitrate levels in the water leaving this drainage system meets the EPA standard for drinking water,” said Dr. Kjaersgaard.
SDSU also has bioreactor research sites near Montrose and Arlington. Dr. Kjaersgaard noted that all of the sites are seeing positive results, but the Baltic site is the top performer.
To learn more about bioreactors, watch the video below. You can also read a past blog post with more information on this innovative conservation drainage system.